Pope Francis has left Rome’s Fiumicino Airport on his second visit to sub-Saharan Africa where he will spend most of the 4-10 September trip in Mozambique and Madagascar and briefly visit Mauritius at the end.

Fires in the Amazon have given new urgency to the Pope’s calls to protect the environment, tackle climate change and promote sustainable development.

His aides said the trip is a key opportunity to renew appeals enshrined in his 2015 encyclical “Laudato Si” on environmental protection.

Francis challenged governments on Sunday to take drastic measures to combat global warming and reduce the use of fossil fuels, saying the world was experiencing a climate emergency.

Francis is also expected to stress the need to bolster Mozambique’s fragile peace process.

The former Portuguese colony emerged from 15 years of civil war in 1992 but it was only last month that President Filipe Nyusi of the ruling Frelimo party and the leader of the Renamo opposition, Ossufo Momade, signed a permanent ceasefire.

With elections scheduled for October, some fear violence may break out.

The topics of poverty and inequality will also loom large on the trip.

According to the U.N. World Food Programme (WFP), 80 percent of Mozambique’s population of about 30 million cannot afford the minimum costs for an adequate diet.

The WFP said more than 90 percent of Madagascar’s population of 26 million live on less than $2 a day and that chronic child malnutrition is widespread.

Francis has called for a fairer distribution of wealth between prosperous and developing countries, and defended the right of countries to control their mineral resources.